Photographic film



Patented Dec. 12, 1933 UNITED STATES PATENT OFFICE PHOTOGRAPHIC FILMEdwin Ernest Jelley, Harrow, England, assignor to Eastman Kodak Company,Rochester, N. Y., a corporation of New York No Drawing. ApplicationNovember 9, 1931, Serial No. 574,047, and in Great Britain August 4,1931 Claims. (Cl. 95-8) This invention relates to photographic films andmay be added may be varied within wide limits plates and moreparticularly to film which-at the depending upon the degree of the matteeffect that option of the user will when finished be either is desired.In general I have found that 1 percent matte or clear. by volume of thegelatin solution that which would 5 Numerous methods of making mattefilm have result in about percent by volume of the dried 60 beensuggested but in all'of them the film furgelatin to be satisfactory.nished by the manufacturer was either perma- In the process of the fithe Organic Salt nently clear or permanently matte. such as calciumbenzoate is transformed in an or:

The present invention provides a photographic dinary alkaline developercontaining soluble alfilm or plate (both of which are hereinafterinkaline carbonate and sulfite into calcium carbon- 5 cluded forconvenience in the expression film) ate and sulfite which remains insuspension in the to which a matte appearance may be imparted layer,giving the layer a matte or opalescent apor not, at will, during thetreatment to which the pearance. On placing this film in an ordinaryfilm is subjected after exposure. For this purfixing bath comprisingsodium thiosulfate and bipose, the matte appearance is produced byresulfite the opalescence will disappear and a clear 7 action between asubstance or substances incorfinished film will result. porated in thefilm and one or more ingredients If a matte surface is desired, the bestresults of a bath or baths used in the after-treatment, are obtainedwhen the film is fixed in such an such as the developing or fixing bath.acid fixing bath containing anions of oxalic acid,

In the preferred form of the invention, the film preferably introducedin the form of an alkali ox- 7 contains a soluble salt of an alkalineearth metal, alate or ammonium oxalate. In such a fixing preferablycalcium. Such salt is preferably inbath, calcium originally present inthe film is corporated in a gelatine layer applied to the back convertedinto crystals of calcium oxalate having of the film, but incorporationof the salt, or of a a diameter varying from about In to 10 and propartof it, in the emulsion layer is not excluded; ducing a matte surfacewhich is easily marked in the case of films coated on both sides withsenby an H or HB retouching pencil. A suitable sitive emulsion, such asfilms intended for X-ray acid fixing bath is one containing about 1perphotography, the salt may be incorporated in cent. of ammoniumoxalate. either or both of the sensitive layers. The film may, ifdesired, be submitted to a 30 In the case of flexible film this backinglayer solution of the oxalate of an alkali after the dewould thenprevent curling. It would also give veloping bath and before the fixingbath with a matte appearance for inspection of the photosimilar results.graph and would have a rough surface for pur- It is also possible toinclude an oxalate in the poses of retouching or for working up thephotodeveloper but I do not find this so satisfactory 35 graph. It couldalso be a carrier for a temporary for retouching purposes since thecrystals thus anti-halation dye. It could also in the case of formed areextremely small. The opalescent apmotion picture film constitute ananti-static layer. pearance is, however, secured. A further modi- Thesalts may also be incorporated in a layer fication of the inventionwould comprise the between the emulsion and the support or above formingor inclusion of calcium carbonate in the 40 the emulsion. film beforeexposure and development. In this In the preferred form of the inventiona solucaseit would remain unchanged by the ordinary ble salt of analkaline earth metal, preferably caldeveloping bath but would be removedin the cium, is used. The backing layer is of a gelatin fixing bath orwould be fixed in position by an and may be prepared by adding the saltdissolved oxalate bath before or combined with the fixing 5 in hot waterto a 15 percent gelatin solution and bath. A further advantage in thepresence of then adding water to bring the gelatin content calciumoxalate is that, if desired, it may be reto 10 percent. The followingcalcium organic moved by treating the photograph with dilute salts havebeen found particularly successful: hydrochloric acid, leaving the filmclear and calcium benzoate; calcium salicylate; calcium transparent.

50 glycerophosphate; calcium lactate; calcium for- I contemplate asincluded within my invenmate, and calcium acetate. In general I havetions all such modifications and equivalents as found that any calciumorganic salt having a fall within the terms of the appended claims.moderate solubility to be satisfactory. By this Having thus described myinvention what I I mean of more than 1 percent and less than say claimas new and desire to secure by Letters 5 30 percent in water. The amountof this that Patent of the United States is:

1. A sensitive photographic element comprising a support with a colloidlayer thereon, there being in the colloid layer a calcium organic salthaving a solubility in water greater than 1 percent and less than 30percent.

2. A sensitive photographic element comprising a support with apermanent colloid layer thereon, there being in the colloid layer acalcium organic salt having a solubility in water greater than 1 percentand less than 30 percent, and having the following properties (a) thatthe salt and the transformation products thereof formed in an ordinarydeveloping bath remain in position therein (b) that the salt andtransformation products thereof formed in an ordinary developing bathare soluble in an ordinary fixing bath, and (c) that the salt and thetransformtion products thereof formed in an ordinary developing bath aretransformable into crystalline particles insoluble in an ordinary fixingbath and which render the element matte.

3. A sensitive photographic element comprising a support with apermanent colloid layer thereon, containing calcium benzoate.

4. A photographic element comprising a sup-. port, a sensitized layer onone surface and a permanent colloid layer on the other surfacecontaining calcium benzoate.

5. A photographic element comprising a support, a sensitive colloidlayer and a second colloid layer containing a calcium organic salthaving a solubility in water greater than 1 per cent and less than 30per cent.

EDWIN ERNEST JELLEY.

